Education

2003. Ph.D. Molecular Biosciences and Bioengineering. University of Hawaii at Manoa.
2000. M.S. Plant Genetics and Breeding. China Agriculture University, P. R. China.
1993. B.S. Cell Biology. Wuhan University, P. R. China.

Research Emphasis:

Flower Development and Sex Chromosome Evolution in Papaya: Unlike most animal species that produce unisexual individuals, the majority of flowering plants produce flowers that are ‘perfect’ and contain both ‘male’ and ‘female’ organs. Less than 10% of plant species produce flowers, which are unisexual. Papaya is a polygamous plant species producing both dioecious and perfect flowers and provides an opportunity for studying flower development in dioecious and hermaphrodite plant species.

The sex determination system in papaya is particularly intriguing, not only because it has three sex types within the species, also because it shows frequent sex reversal caused by environmental factors. Recent studies showed that sex determination in papaya is controlled by a pair of primitive sex chromosomes. We are working on physical mapping and sequencing the male specific Y chromosome (MSY) and its corresponding region on X chromosome as the first step towards cloning the sex determination genes in papaya.

Papaya Genomics: Papaya is diploid species with 9 pairs of chromosomes. Its genome size is 372 Mb, which is smaller than most of other plant genomes. The generation time of papaya is as short as 9 month. Because papaya is a polygamous species, hand-pollination is easily done. From each hand-pollinated fruit, it produces 800 to 1,000 seeds. Vegetative propagation is possible by cuttings or by tissue culture. A genetic transformation system is well established. The above favorable properties make papaya an excellent model system of fruit trees for genomic studies.

The draft sequence with 3X coverage of papaya genome has been finished by the Hawaii Papaya Genome Consortium. A high-density genetic map with 706 sequence-based SSR markers and a FPC-based physical map have been constructed. With these genetic and genomic resources available, we are mapping quantitative trait loci controlling agronomically important traits (such as fruit size and fruit weight) and cloning genes related to nutritional profile (such as flesh color) for papaya improvement.

Recent Publications

Yu, Q., E. Tong, R.L. Skelton, J.E. Bowers, M.R. Jones, J.E. Murray, S. Hou, P. Guan, R.A. Acob, M.C. Luo, P.H. Moore, M. Alam, A.H. Paterson, R. Ming. 2009. A physical map of the papaya genome with integrated genetic map and genome sequence. BMC Genomics 10: 371.

Zhang W., X. Wang, Q. Yu, R. Ming, and J. Jiang. 2008. DNA methylation and heterochromatinization in the male-specific region of the primitive Y chromosome of papaya. Genome Research 18: 1938-1943 (Cover story).

Ming R.*, S. Hou*, Y. Feng*, Q. Yu*, A. Dionne-Laporte, J.H. Saw, P. Senin, W. Wang, B.V. Ly, K.L.T. Lewis, et al. 2008. The draft genome of the transgenic tropical fruit tree papaya (Carica papaya Linnaeus). Nature 452:991-996 (*equal contribution) (cover story).

Yu, Q., R. Navajas-Pérez, E. Tong, J. Robertson, P.H. Moore, A.H. Paterson, R. Ming. 2008. Recent origin of dioecious and gynodioecious Y chromosomes in papaya. Tropical Plant Biology 1:49-57.

Yu, Q., D. Steiger, E.M. Kramer, P.H. Moore, R. Ming. 2008. Floral MADS-box genes in trioecious papaya: Characterization of AG and AP1 subfamily genes revealed a sex-type-specific gene. Tropical Plant Biology 1: 97-107.

Yu, Q., S. Hou, F.A. Feltus, M.R. Jones, J.E. Murray, O. Veatch, C. Lemke, J. H. Saw, R.C. Moore, J. Thimmapuram, L. Liu, P.H. Moore, M. Alam, J. Jiang, A.H. Paterson, R. Ming. 2008. Low X/Y divergence in four pairs of papaya sex linked genes. Plant J. 53:124-132. (cover story)

Texas A&M University - Department of Plant Pathology & Microbiology - Dr. Leland S. Pierson III, Professor and Head
120 Peterson 2312 TAMU College Station, TX 77843-2312  Phone (979) 845-8288   Email: plpm-head@ag.tamu.edu